portass
A breviary; a prayer book.
obsolete
an old Priest in that age, which always read in his Portass, Mumpsimus Domine for Sumpsimus; whereof when he was admonished, he said that he now had used Mumpsimus thirty years, and would not leave his old Mumpsimus for their new Sumpsimus.
Where it comes from
From Middle English porthors, from Old French porte-hors (“a kind of portable prayer-book”).
Adapted from the Wiktionary entry portass (CC BY-SA 4.0).